In recent years, endoscopic surgical operations (also called laparoscopic surgery) are attracting attention. Used in the endoscopic surgical operations is a surgical instrument configured by attaching a surgical tool to a tip end of a shaft. Examples of the surgical tool include forceps, graspers, scissors, staplers, needle holders, and electric scalpels. These surgical tools are used in accordance with contents of operations. In the endoscopic surgical operations, one or a plurality of holes are opened at, for example, an abdominal part of a patient, and a trocar is inserted as a passage port for tools. After that, a laparoscope and a surgical tool are inserted into a coelom through the trocar, and surgery for an affected part of the patient is performed. A surgeon monitors treatments by utilizing a monitor displaying an image of a surgical portion photographed by the laparoscope and operates the surgical instrument from an outside of the abdominal part.
Each of PTLs 1 and 2 shows this type of surgical instrument. A surgical instrument (medical manipulator) of PTL 1 includes: a connecting block; a distal-end working unit including a surgical tool; a shaft coupling the connecting block and the distal-end working unit to each other; and an actuator configured to drive the distal-end working unit by a wire. The shaft includes a first intermediate joint and a second intermediate joint. Each of the intermediate joints is formed such that a plurality of circular plate-shaped segments are stacked in a direction parallel to an axial direction of the shaft. The wire is inserted through the segments. The joints are bent by relaxing and tensing of the wire. Further, regarding three successive segments, a second segment is coupled to a first segment so as to be rotatable about a first axis perpendicular to the axial direction of the shaft, and a third segment is coupled to the second segment so as to be rotatable about a second axis that is perpendicular to the axial direction of the shaft and is different in phase by 90° from the first axis.
A surgical instrument (surgical device) of PTL 2 includes: a housing; a shaft extending from the housing; and an end effector provided at a tip end of the shaft. The shaft includes at least one articulating portion, and the articulating portion is formed by a plurality of joints which are nestingly arranged in series. Each of the plurality of joints includes a distal knuckle and a proximal clevis, and each knuckle operatively engages a clevis of an adjacent joint.